Conventionally, atomizers charged with propellant gases have been used widely.
However, these atomizers have a drawback that the propellant gases used therein may affect the human body adversely or may explode.
For this reason, so-called manually operative compact sized atomizers are now under reconsideration. However, in the conventional manually operative atomizer, it is difficult to obtain a sufficient atomizing pressure especially at the beginning of the atomization, so that a fine atomization cannot be obtained at the beginning period.
In order to avoid this problem, the present applicant has proposed an atomizer of accumulator type, as in the U.S. Pat. No. 3,908,870 by the present applicant. This accumulator type atomizer has a discharge valve adapted to remain closed until a sufficiently high pressure is established. Thus, the discharge valve does not immediately open at the beginning of the depression of the atomizer head, rather it is allowed to open only after the required pressure is established, so as to provide a fine atomization.
Although this accumulator type atomizer provides a practical solution to the above mentioned problem, another problem has arisen, namely a considerably large force is required for depressing the atomizer head to overcome the force applied to the discharge valve in such atomizers.
The large depression force on the atomizer head is also necessary in other types of atomizers in addition to that of the accumulator type, especially when the amount of spray at one operation is quite large.
Since the handiness and easiness in the atomization operation is an important feature of atomizers, an exceedingly large force must not be required for the depression of the atomizing head.